Support assembly for a portable surface-treating machine

ABSTRACT

An electrically-driven portable surface-treating machine having the motor and means driven thereby for oscillating a platen mounted within a clamshell housing. The oscillatable platen is connected to the housing through securement of a plurality of resilient posts connected to the housing. The posts are formed with flanges which are retained within the recesses formed transversely in the housing and there are pairs of such posts at respective ends of the housing, a flange of each pair of posts being in abutting relationship. The posts are molded in a one step operation with a hollow body portion extending from the flange downwardly and being shaped adjacent the bottom of the hollow to receive a nut which is subsequently inserted from the open top of the body portion to nest adjacent to the bottom of the post. After the posts are disposed in the housing, screws will be threadedly connected to the nut to thus secure the platen at the bottom of the posts.

United States Patent [191 Klebe, Jr. et a1.

[451 Jan. 28, 1975 SUPPORT ASSEMBLY FOR A PORTABLE SURFACE-TREATING MACHINE [75] Inventors: Elmer C. Klebe, Jr., Easley;

- Timothy J. Looper, Pickens, both of [73] Assignee: The Singer Company, New York,

[22] Filed: Aug. 9, 1974 [21] Appl. No.: 495,935

Related US. Application Data [63] Continuation-impart of Ser. No. 442,518, Feb. 14,

3,336.702 8/1967 Enders 51/170 MT 3,747,280 7/1973 Stroezel 51/170 MT 3,815,292 6/1974 Hutchins 51/170 MT Primary Examiner--Donald G. Kelly Attorney, Agent, or Firm-Marshall .1. Breen'. Edward L. Bell; Harold Weinstein [57] ABSTRACT An electrically-driven portable surface-treating machine having the motor and means driven thereby for oscillating a platen mounted within a clamshell housing. The oscillatable platen is connected to the housing through securement of a plurality of resilient posts connected to the housing. The posts are formed with flanges which are retained within the recesses formed transversely in the housing and there are pairs of such posts at respective ends of the housing, a flange of each pair of posts being in abutting relationship. The posts are molded in a one step operation with a hollow body portion extending from the flange downwardly and being shaped adjacent the bottom of the hollow to receive a nut which is subsequently inserted from the open top of the body portion to nest adjacent to the bottom of the post. After the posts are disposed in the housing, screws will be threadedly connected to the nut to th-us secure the platen at the bottom of the posts.

6 Claims, 6 Drawing Figures SUPPORT ASSEMBLY FOR A PORTABLE SURFACE-TREATING MACHINE CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of our copending application, Ser. No. 442,518, filed Feb. 14, 1974, for Portable Surface-Treating Machine With Improved Platen-Mounting Construction.

BACKGROUND OF THE INVENTION It has been known heretofore to provide electrically driven portable surface-treating machines such as sanders, polishers, buffers and the like with an oscillatable platen which is connected to the housing of the machine through securement to a plurality of resilient posts. Generally, pairs of such posts are positioned at opposed ends of the machine. The housing for such machines is frequently formed by a pair of complementary mating halves which are detachably secured along the longitudinal axis of the machine. Such housings are known in the art generally as clamshell housings.

In order to impart the desired motion of the platen of such a machine as hereinbefore referred to, it has been found desirable to connect the platen to a plurality of such resilient posts. However, to insure proper initial seating and avoid subsequent accidental displacement of the posts during normal operation of the machine, as well as to facilitate integration of the platen subassem bly with the housing, various expedients have been adopted. One such prior construction utilizes a specially deformed back plate for the platen subassembly in combination with a bracket in order to locate the base flanges of the resilient posts with respect to the platen and permanently affix them in place. A spacer member is sometimes used at the top of adjacent posts which posts also act in concert with a specially designed groove and annular tongue in the housing for positioning of the upper segments of the posts. Thus, there has been a long standing need for improving the constructional arrangement by which the platen is secured to the housing through the use of the resilient posts.

SUMMARY OF THE INVENTION It is one object of the invention to provide an electrisally-driven portable surface-treating machine in which an oscillatable platen is supported by a plurality of resilient hollow posts without any substantial risk of unintended post displacement and without requiring the use of a separate spacer element, which overcomes the prior art deficiencies; which uses hollow posts receiving nut inserts therein after molding; and which is simple, economical and reliable.

It is another object of the invention to provide an electrically-driven portable orbital sander having an oscillatable platen subassembly which can more easily be mounted to a clamshell housing and which uses hollow posts in pairs which are self-locking within the clamshell housing; and which hollow posts require a nut insert therein after molding.

Other objects and advantages of the invention will be readily apparent from the following description of one embodiment of the invention, and the novel features will be particularly pointed out in the claims.

The present invention thus, provides a support as sembly for an electrically-driven portable surfacetreating machine in which the motor and means driven thereby for oscillating a platen are mounted within a clamshell housing having a first and second complementary segment, the support assembly comprising:

a. a plurality of resilient posts including a hollow column terminating in a substantially perpendicularly extending flange,

b. the hollow column having an internally extending shoulder formed adjacent the bottom thereof,

c. a nut insertable into the column to nest upon the shoulder,

d. a plurality of recesses formed in the segments of the housing extending in aligned pairs transversely disposed on either side of the clamshell housing,

e. the flanged end of one of the posts is disposed in each of the recesses to place the posts in pairs connected to opposite segments of the clamshell housing whereby the flanged ends will abut each other to hold the posts securely within the recesses, and

f. a plurality of screw means passing through the platen to secure the same to each ofthe resilient posts by threadedly engaging the nut whereby the'platen and housing will be resiliently connected to permit the platen to oscillate.

BRIEF DESCRIPTION OF THE DRAWINGS This invention is illustrated in the accompanying drawings in which:

FIG. 1 is a perspective-view of a surface-treating machine embodying the invention;

FIG. 2 is an enlarged side elevational view, with the housing partly broken away and partly in section, of the machine shown in FIG. 1;

FIG. 3 is a sectional view of the machine shown in FIG. 2 taken along line 33 thereof;

FIG. 4 is a perspective view, partly in section, of an improved resilient hollow post with the nut inserted therein;

FIG. 5 is a pre-assembled sectional view of the improved post showing the nut being inserted therein; and

FIG. 6 is an assembled sectional view of the improved post showing the nut nested therein.

DESCRIPTION OF THE INVENTION In the illustrated embodiment of the invention, there is shown in FIGS. 1 and 2, an electrically-driven portable surface-treating machine 10 which for purposes of explaining the invention is depicted as a sander. The machine 10 is provided with a clamshell housing 12 comprising a pair of complementary halves l4, 16 which are detachably connected along a longitudinal split 17 by fastening means such as carriage bolts 18 which are desirably spaced at intervals which will assure close mating of the shell halves l4, 16. The machine 10 is provided with slots 20 for the entry of cooling air for the motor and with at least one slot 22 for the exit of the air from the machine 10. A handle 24 is desirably formed integral with the housing l2. An electric switch 26 is mounted in the handle 24 whereby the operator can energize the motor 28 shown in FIG. 2 through the switchs connection through a line 29 with a source of electric power (not shown).'A forwardly positioned auxiliary handle 30 is also provided, preferably formed integral with the housing 12, so that the machine l0v may be grasped by the operator with both hands for easy manual control. A platen subassembly 32 illustrated in FIGS. 1, 2, and 3 is connected to the housing at the bottom thereof, as more fully explained hereinafter. It will be understood, of course, that the platen assembly can be driven so as to provide for any type of shiftable motion be it oscillatory, reciprocatory, orbital or the like.

The motor 28 shown in FIG. 2 is mounted within the housing 12 and the armature shaft 34 thereof is furnished with a fan 36 to induce cooling air through slots 20. A pinion 36 is formed at the lower end of the shaft 34. A reduction gear mechanism 38 is journaled within the housing 12 and is provided with a gear 40 engageable with the pinion 36. The gear 40 is mounted on a stub shaft 42 which rotates with gear 40 and has an eccentric crank 44 formed at its lower end to connect into and eccentrically drive a bearing bracket 46 which is mounted on the back plate 48 of the platen subassembly 32 to thus impart the oscillatory motion to the platen 32.

As is depicted more clearly in FIGS. 2 and 3, the platen subassembly 32 includes a resilient pad 50 which is bonded to the rigid back plate member 48. Both the pad 50 and back plate 48 are preferably essentially planar except for the terminal longitudinally extending edges 52 of the back plate 48 which are turned up along at least a substantial portion of their lengths. The platen subassembly 32 in its preferred form is rectangular in plan view as can be seen most clearly from FIG. 1. The pad 50 and back plate 48 are provided adjacent each of their four corners with through apertures 54, 56 respectively. The apertures 54 and 56 are aligned, with the aperture 54 larger than the aperture 56. A metal screw 58 illustrated in FIG. 3,-*has a head 60 sized to fit into aperture 54 but is larger than aperture 56. Screw 58 has a threaded shank 62 whose diameter is smaller than the aperture 56, so that as seen in FIG. 3, the screw 58 will pass upwardly into and extend outwardly from the platen assembly 32. The screws 58 will be fastened at the bottom of a resilient post 64, pairs of which having been previously affixed within the housing 12 to generally define a support assembly 66, as more fully described hereinafter.

The housing 12 is, as aforestated, of the clamshell type. It is provided at each end with a transversely extending, generally U-shaped recess 68 dimensioned to receive a top flange 70 which is formed on each of posts 64 as hereinafter described. As shown most clearly in FIG. 3, a pair of posts 64 are positioned one in each of the segments 14 and 16 of the housing 12, each such pair comprising first and second posts which are spaced from each other and are located on opposite sides of the longitudinal split 17 of the housing 12.

Each such post 64 is provided with a top flange 70 as shown in FIGS. 2, 3, and 4 of generally rectangular configuration. The thickness of the flange 70 is such that upon assembly with the housing 12 the flange 70 will be accepted within the recess 68. Preferably a sliding fit between the flange and internal walls of the recess is provided although the height of the recess may be tapered slightly from the opening at the longitudinal split 17 in the housing 12 to the outer sidewall of the housing 12 to enhance retention of'the flange within the recess. It will also be appreciated that by forming the recess with a tapered height the insertion of the flange into the recess 'during assembly will be facilitated, thereby aiding assembly in the mass production of the machine 10.

In the preferred embodiment, the resilient posts are the principal component of the support assembly 66,

and are-formed ofa hard rubber or other suitable elastomer material which permits a controlled degree of flexibility thereof. The resilient posts 64 have a hollow cylindrical body portion 72 through which a central aperture 74 extends. The aperture 74 has three sections: an upper section 76 which extends axially downwardly from an open top edge 78, at the flange end of the post 64, some 70 percent of the length of the body 72 to terminate at an upper shoulder 82; an intermediate section 80 which is formed between the upper shoulder 82 and a lower shoulder 84; and a lower section 86, which extends from the lower shoulder 84 to the flat bottom edge 88. The lower section 86 has a circular opening therein of similar diameter as the aperture 56 formed in the plate member 48. The intermediate section 80 has a hexagonal shape 90 which corresponds to the hexagonal body 92 of a nut 94 as shown in FIGS. 4, 5, and 6. The length of each of the sections 80 and 86 is roughly equal and amounts to some 30 percent of the body 72 length. The body portion 72 has its greatest resiliency along the upper section 76 where the annular walls 96 is the thinnest. One end 70a of the flange preferably begins at the face of the underlying wall 96 of body 72 and the flange 70 extends substantially beyond the face of the opposed side of wall 96 of body 72. The overall length of the flange 70 is such that when both halves l4 and 16 of the housing 12 are brought together into mated relationship, the end faces 70b of the flanges 70 of each respective pair of posts 64 adjacent the longitudinal split 17 of the housing 12 are brought into abutting relationship. Such cooperative dimensioning of the lengths of the abutting flanges 70 aids in self-locking of the upper segments of the posts 64 within the recesses 68. This self-locking feature may also be achieved by dimensioning the length of each flange 70 such that it is slightly longer than the transverse extent of the recess in which it is received. Such constructions for the abutting flanges serves to maintain the upper segments of the posts in their designed positions within the housing and thereby provide the desired degree of stability for the mounting of the platen. Of course, it will be appreciated that one of the flanges may be formed slightly smaller in length than the length of the recess whereas its abutting flange may be formed with a length sufficiently great so that the desired abutment between contiguous flanges nevertheless occurs.

The post 64 is molded in a one step operation and subsequent to removal from the mold the nut 94 will be inserted therein as shown in FIG. 5. The nut has a seating flange 98 formed at its upper end, the diameter of which is substantially equal to the diameter of the upper section 76. The nut-94 has a cup shaped bottom 100 with a central aperture 102 sized to engage the threaded shank 62 of the screw 58. The insertion of the nut 94 into the central aperture 74 will be complete when the seating flange 98 is nesting upon the upper shoulder 82 as illustrated in FIG. 6. The lower shoulder 84 serves as a secondary stop to prevent the nut 94 from descending any lower whenever the bottom 100 contacts the lower shoulder 84. Also the two shoulders 82 and 84 construction would serve to uniformly distribute the forces exerted on the post 64 by the threaded connection between the screw 58 and the nut 94 by providing two spaced contact points.

The posts 64 extend from the flange 70 connection in the recesses 68 of the housing 12 downwardly as illustrated in FIGS. 2 and 3 to have the flat bottom edge 88 rest upon the upper surface of the back plate 48 of the platen subassembly 32. The central aperture 74 of the post 64 is aligned with the holes 54 and 56 of the platen 32. As shown in FIG. 3, screws 58 are inserted upwardly through apertures 54, 56 of the pad 50 and back plate 48, respectively, and screwed into nuts 94 to releaseably lock the platen subassembly 32 to the bottoms of the posts 64 at each corner of the housing. Upon the screw 58 being tightened to bring its head 60 into contact with the back plate 48 continued turning will force the nut 94 downwardly toward the platen 32 causing slight deformity of the post 64 in the area of the shoulders 82, 84 to bring the lower shoulder 84 into firm contact with the bottom 100 of the nut 94, thus assuring the two point contact and firm connection between the platen 32 and the posts 64.

As may be clearly seen from FIGS. 2 and 3 of the drawings the posts 64 are desirably positioned one adjacent each corner of the housing 12. The flanges 70 of the pairs of posts 64 at each end of the housing on opposite sides of the longitudinal split 17 in the housing 12 extend a substantial distance beyond the body ofthe post 64 towards the inner portion of the housing. The total length of the flanges 70 are preferably approximately twice the diameter of the post body 72 although such proportion is by no means critical. Thus, during operation of the machine the upper and lower segments of the posts 64 are maintained in relatively stable and fixed relationship relative to the housing 12 and platen 32 to which they are secured. Yet the upper section 76 of the body 72 is afforded the degree of resiliency necessary to impart the desired oscillatory motion to the platen 32.

From the foregoing it will be seen that Applicant has provided an extremely simple construction for securing the oscillatable platen 32 to the housing 12 by means of the plurality of resilient posts 64. Nevertheless, the resilient posts 64 are maintained within the housing 12 at the predetermined designed locations by virture of the particular flange 70 construction retained within the transverse recess 68 in the housing 12 and through use of the inserted fastening means namely nuts 94 at the other end of the posts 64 to the platen subassembly 32.

It will be understood that various changes in the details, materials, arrangements of parts and operating conditions which have been herein described and illustrated in order to explain the nature of the invention may be made by those skilled in the art within the principles and scope of the invention.

Having thus set forth the nature of the invention, what is claimed herein is:

1. A support assembly for an electrically-driven surface-treating machine in which the motor and means driven thereby for oscillating a platen are mounted in a clamshell housing having a first and a second complementary segment, the support assembly comprises:

a. a plurality of resilient posts including a hollow column terminatinng in a substantially perpendicularly extending flange,

b. the hollow column having an internally extending shoulder formed adjacent the bottom thereof,

c. a nut insertable into the column to nest upon the shoulder.

d. a plurality of recesses formed in the segments of the housing extending in aligned pairs transversely disposed on either side of the clamshell housing,

e. the flanged end of one of the posts is disposed in each of the recesses to place the posts in pairs connected to opposite segments of the clamshell housing whereby the flanged ends will abut each other to hold the posts securely within the recesses, and

f. a plurality of screw means passing through the platen to secure the same to each of the resilient posts by treadedly engaging the nut whereby the platen and housing will be resiliently connected to permit the platen to oscillate.

2. The combination claimed in claim 1 wherein:

a. the post has a central aperture with aan upper section oflargest diameter, an intermediate section of intermediate diameter and a lower section of smallest diameter,

b. an upper shoulder formed at the bottom of the upper section,

c. a lower shoulder formed at the bottom of the intermediate section, and

the nut nests on at least one of the shoulders. The combination claimed in claim 2 wherein: the nut having a body,

a flange extending from the body, and the flange to engage one of the shoulders to limit the insertion of the nut within the aperture of the post.

The combination claimed in claim 3 wherein:

a. the flange formed on the upper end of the body of the nut, and

b. the flange to engage the upper shoulder upon the nut being inserted into the aperture of the post.

5. The combination claimed in claim 4 wherein:

. the body of the nut to be in spaced relation to the lower shoulder upon insertion of the nut within the aperture whereby on tightening of the screw within the nut, the nut to be forced increasingly downwardly to seat the bottom of the body upon the lower shoulder.

. The combination claimed in claim 2 wherein:

a. the nut having a body shaped hexagonally, and

b. the intermediate section of the aperture hexagonally shaped corresponding to the nut body and adopted to receive the same in non-turning engagement therewith. 

1. A support assembly for an electrically-driven surfacetreating machine in which the motor and means driven thereby for oscillating a platen are mounted in a clamshell housing having a first and a second complementary segment, the support assembly comprises: a. a plurality of resilient posts including a hollow column terminatinng in a substantially perpendicularly extending flange, b. the hollow column having an internally extending shoulder formed adjacent the bottom thereof, c. a nut insertable into the column to nest upon the shoulder, d. a plurality of recesses formed in the segments of the housing extending in aligned pairs transversely disposed on either side of the clamshell housing, e. the flanged end of one of the posts is disposed in each of the recesses to place the posts in pairs connected to opposite segments of the clamshell housing whereby the flanged ends will abut each other to hold the posts securely within the recesses, and f. a plurality of screw means passing through the platen to secure the same to each of the resilient posts by treadedly engaging the nut whereby the platen and housing will be resiliently connected to permit the platen to oscillate.
 2. The combination claimed in claim 1 wherein: a. the post has a central aperture with aan upper section of largest diameter, an intermediate section of intermediate diameter and a lower section of smallest diameter, b. an upper shoulder formed at the bottom of the upper section, c. a lower shoulder formed at the bottom of the intermediate section, and d. the nut nests on at least one of the shoulders.
 3. The combination claimed in claim 2 wherein: a. the nut having a body, b. a flange extending from the body, and c. the flange to engage one of the shoulders to limit the insertion of the nut within the aperture of the post.
 4. The combination claimed in claim 3 wherein: a. the flange formed on the upper end of the body of the nut, and b. the flange to engage the upper shoulder upon the nut being inserted into the aperture of the post.
 5. The combination Claimed in claim 4 wherein: a. the body of the nut to be in spaced relation to the lower shoulder upon insertion of the nut within the aperture whereby on tightening of the screw within the nut, the nut to be forced increasingly downwardly to seat the bottom of the body upon the lower shoulder.
 6. The combination claimed in claim 2 wherein: a. the nut having a body shaped hexagonally, and b. the intermediate section of the aperture hexagonally shaped corresponding to the nut body and adopted to receive the same in non-turning engagement therewith. 